1. Field of the Invention
The present invention relates to a dumping device and a dumping method for unloading used catalyst adhered and agglomerated inside a reactor of petroleum refining plant, chemical plant and the like.
2. Description of Related Art
Various catalysts are used in a petroleum refining plant, chemical plant and the like for facilitating chemical reactions. The catalysts are used being filled inside a reactor for circulating fluid material.
Such catalysts have to be periodically unloaded from the reactor to be exchanged, since activity of the catalyst gets weak as the catalysts are poisoned by sedimentation of carbide, metal or the like and the catalysts are smashed on account of lowering of mechanical strength. The catalysts also need to be unloaded from the reactor for repairing or examining the plant.
[Unloading Condition of Catalyst]
The catalysts need to be unloaded in a short time period for minimizing plant shut-down time.
Further, since the catalyst in operation is often in a reducing atmosphere, carbide, sulfur etc. adhered to the catalyst while the catalyst is used can generate heat on account of oxidization of the catalyst when the catalyst is made open to the air for exchanging the catalyst. Accordingly, the unloading work has to be appropriately performed considering accompanying bad influence of the heat, and, further, dust of the catalyst on human body.
Further, nitrogen gas is supplied into the reactor for preventing ignition caused by oxidization of the catalyst when the reactor is big, so that the work is conducted under nitrogen gas atmosphere.
[Actual Catalyst Unloading]
Conventionally, following methods are known for unloading the catalyst from the reactor.
(1) Unloading the catalyst from catalyst dumping nozzle provided on a lower part of the reactor.
(2) Vacuum unloading the catalyst from a manhole provided onto a top part of the reactor.
Which one of the above methods should be selected is determined by a supervisor after opening the catalyst dumping nozzle of the reactor to examine whether the inside catalyst can be unloaded or not. When the catalyst is not agglomerated and can be unloaded from the catalyst dumping nozzle, the unloading work is conducted according to above (1) method.
On the other hand, when the catalyst is agglomerated and can not be unloaded from the catalyst dumping nozzle, the unloading work is performed according to above (2) method. In other words, after discharging reacting material such as crude oil before the vacuum unloading, the agglomerated catalyst is smashed using a spade etc., or alternatively, a pick etc. driven by air or oil pressure when the catalyst is especially agglomerate. Subsequently, the smashed and powdered catalyst is sucked in by a vacuum hose and the like from the manhole side to discharge to a hopper etc.
[Problem in Unloading Catalyst]
Though the catalyst in the reactor is agglomerated, the carbide and the like adhered to the catalyst can be oxidized to generate heat when the catalyst is made open to the air. In this case, the unloading work is difficult on account of a high temperature of the reactor. Further, when the work is carried out in the nitrogen gas atmosphere, the unloading work is difficult to be performed in the reactor. Accordingly, long time is necessary for the unloading work of the catalyst inside the reactor, so that the work efficiency is deteriorated and the plant shut-down time is prolonged.
Further, according to the conventional vacuum unloading method, the catalyst dumping nozzle is opened to examine whether the catalyst can be discharged therefrom. Consequently, when the catalyst can not be discharged from the catalyst dumping nozzle, the unloading process has to be changed to perform the vacuum unloading using the vacuum hose from the upper manhole. Accordingly, the work efficiency is bad for the extra process. Further, since the catalyst is sucked in by the vacuum hose while smashing the catalyst, the catalyst has to be smashed considerably small and the vacuum hose has to be drawn to the smashed spot. Therefore, a plurality of workers are necessary, thereby further deteriorating work efficiency.
According to the conventional vacuum unloading method, a special vacuum apparatus is necessary, thereby requiring extra costs.
Since the catalyst is sucked at an intense speed according to the conventional vacuum unloading method, the catalyst is often smashed to cause almost 20% catalyst loss, thereby causing bad yield rate for recycling the catalyst.
The object of the present invention is to provide a dumping device and a dumping method for unloading catalyst inside a reactor which can improve work efficiency, do not require a special apparatus such as a vacuum apparatus and can prevent the catalyst from being smashed to decrease loss of the catalyst.
For the object, the smashed catalyst is unloaded by dropping the used catalyst inside the reactor by virtue of gravity according to the present invention.
A catalyst dumping device according to the present invention is for unloading used catalyst from an inside of a reactor. The catalyst dumping device has a catalyst dumping-out member extending perpendicularly inside the reactor and further extending from an inside to an outside of the reactor, the catalyst dumping-out member having a falling passage of the used catalyst smashed thereinside, and an upper end of the catalyst dumping-out member is located adjacent to an uppermost surface of the catalyst.
In the above arrangement, the catalyst dumping-out member is preferably a pipe member having inner diameter large enough for a block of catalyst of a certain size, not only minutely smashed catalyst, to pass through. A single member is possible, however, it is preferable that the catalyst dumping-out member can be divided into a predetermined length for convenience of installing and handling.
The catalyst dumping-out member is preferably made of anticorrosive stainless steel. However, the catalyst dumping-out member may be made of an ordinary steel anticorrosively processed. Alternatively, the catalyst dumping-out member may be made of ceramics, earthenware pipe or concrete. Paper can also be used for convenience of disposal. Further, heat-resistant synthetic resin pipe having flexibility may be used considering facilitation of installment and detachment.
Accordingly, the catalyst inside the reactor is thrown into the catalyst dumping-out member installed inside the reactor after being smashed and is unloaded by a fall.
Since the catalyst inside the reactor can be unloaded only by being thrown into the dumping-out member installed in the reactor, work efficiency can be improved. Since no special apparatus such as a vacuum apparatus is unnecessary, the cost can be reduced.
Since the smashed catalyst can be unloaded only by being thrown into the dumping-out member, fewer workers are necessary than the vacuum method requiring workers for smashing the catalyst and the workers for sucking the smashed catalyst by a vacuum apparatus. Accordingly, when there is the same number of workers as in the vacuum method, approximately twice as much as work, simply calculated, can be done by the workers smashing and throwing the catalyst, thereby also improving the work efficiency in this respect.
Since the catalyst is thrown into the dumping-out member being smashed at a certain size to be fallen and unloaded, the catalyst can be prevented from being broken into pieces, so that the catalyst loss can be decreased.
The catalyst dumping-out member preferably includes a plurality of pipe members connected with each other.
Accordingly, the catalyst dumping-out member can be constructed using a plurality of pipe member. Since each pipe member can be handled easily, the catalyst dumping-out member can be easily installed and removed.
The pipe members are preferably connected by fitting an insert provided to a lower bulge of a pipe member to a fitting portion provided to an upper bulge of a pairing pipe member. The insert preferably includes an inner ring portion formed successively to an inner diameter of the pipe member, an outer ring portion consecutive to an outer diameter and a groove portion formed between the ring portions. And the fitting portion preferably includes first abutting portion formed to the lower bulge of the pairing pipe member capable of being abutted to an upper side of the inner ring portion, a protrusion protruding downward from the first abutting portion and second abutting portion capable of being abutted to an upper side of the outer ring portion.
The inner ring portion and the outer ring portion of the fitting portion may be located coplanarly, or on different planes. A gap may preferably formed between a distal end of the protrusion of the pairing pipe member and a bottom of the groove portion of the pipe member for gasket etc. to be packed therein.
According to the above arrangement, the pipe members are connected by fitting the insert of the pairing pipe member to the fitting portion of the pipe member, so that the connecting portion is nested and sealability inside the pipe members can be ensured. Therefore, process fluid for the catalyst such as crude oil can be prevented from flowing into the pipe members. Consequently, the process fluid and the catalyst can work as designed for performing sufficient function of the catalyst.
The connecting portion of the respective pipe members is preferably provided with a sealing member for preventing process fluid for catalyst from flowing into an inside of the pipe members from outside by virtue of a pressure difference between the inside and outside of the pipe members.
The sealing member is, for instance, packing or gasket, which is preferably accommodated in a gap between the protrusion of the connecting portion of the pipe members and the groove portion.
Accordingly, the pressure difference between the inside and the outside of the pipe members can be decreased by virtue of the sealing member provided to the respective connecting portion of the pipe members. Therefore, process fluid for the catalyst can be prevented from flowing into the inside of the pipe members from the outside. Consequently, the process fluid and the catalyst can work as designed for performing sufficient function of the catalyst.
A high-density member having larger density than the catalyst is preferably filled inside the respective pipe members for preventing process fluid for catalyst from flowing into an inside of the pipe members from an outside by virtue of a pressure difference between the inside and the outside of the pipe members.
Any material can be used for the high-density member as long as it has larger density than the catalyst, such as sand or ceramic sand.
Accordingly, the pressure difference between the inside and the outside of the pipe members can be decreased by virtue of the high-density member filled inside the respective pipe members. Therefore, process fluid for the catalyst can be prevented from flowing into the inside of the pipe members from the outside. Consequently, the process fluid and the catalyst can work as designed for performing sufficient function of the catalyst.
The respective pipe members are preferably provided with a lifting member for suspending and lifting the respective pipe members.
Any arrangement can be adopted for the lifting member, for example, in which a nut-shaped member is attached to the pipe member and a stick member is engaged thereto for hanging and lifting by a wire etc., or a ring-shaped member is movably attached to the pipe member for hanging and lifting by a hook attached to a wire etc.
According to the above arrangement, the respective pipe members can be hanged and lifted by the lifting member, thereby facilitating attachment and detachment of the pipe members.
A nozzle is preferably provided approximately at an extended position of the catalyst dumping-out member for the catalyst dumping-out member to pass through.
Accordingly, when the catalyst dumping-out member is detached, the catalyst dumping-out member can be taken out from the nozzle provided approximately at the extended position of the catalyst dumping-out member without moving the catalyst dumping-out member in a transverse direction inside the reactor, thereby facilitating the detachment work of the catalyst dumping-out member.
A catalyst dumping method according to the present invention is for unloading used catalyst from an inside of a reactor. The catalyst dumping method is characterized in having the steps of: providing a catalyst dumping-out member inside the reactor extending perpendicularly inside the reactor and further extending from the inside of the reactor to an outside of the reactor, the catalyst dumping-out member having a plurality of pipe members connected with each other provided thereinside with falling passage for a smashed catalyst; smashing the catalyst; throwing the smashed catalyst into an uppermost pipe member; while continuing the smashing and throwing steps, detaching the connected pipe members sequentially from an upper pipe member in accordance with lowering of a level of an upper surface of the catalyst; and continuing to throw the smashed catalyst into the pipe member of corresponding level of the upper surface of the catalyst, thereby unloading the catalyst inside the reactor.
According to the above arrangement, the catalyst inside the reactor is thrown into the catalyst dumping-out member installed inside the reactor after being smashed and is unloaded by a fall. Since the catalyst inside the reactor can be unloaded only by being thrown into the dumping-out member installed in the reactor, work efficiency can be improved. Since no special apparatus such as a vacuum apparatus is unnecessary, the cost can be reduced.
Since the smashed catalyst can be unloaded only by being thrown into the catalyst dumping-out member, fewer workers are necessary than the vacuum method requiring workers for smashing the catalyst and the workers for sucking the smashed catalyst by a vacuum apparatus. Accordingly, when there is the same number of workers as in the vacuum method, approximately twice as much as work, simply calculated, can be done by the workers smashing and throwing the catalyst, thereby also improving the work efficiency in this respect.
Since the catalyst is thrown into the dumping-out member being smashed at a certain size to be fallen and unloaded, the catalyst can be prevented from being breaking into pieces, so that the catalyst loss can be decreased.